The long-term goal of this research is to improve exposure assessment methods for epidemiological studies of agricultural pesticide use and cancer. The specific aims of this research proposal are: 1. To validate a set of geographic-based metrics for exposure assessment to agricultural pesticides using environmental samples of household dust. 2. To evaluate change in predicted land cover for use in a geographic-based exposure metric over a multi-year period. 3. To evaluate how seasonal calculation of a metric for exposure to agricultural chemical use effects potential household exposure. A procedure has been developed for predicting the likelihood that pesticides used in agricultural operations in the vicinity of a residence will be transported to inside the residence. This study is designed to use measurement of agricultural pesticides in household dust to test the validity of the procedure.